Emergency communication systems are being upgraded on a regular basis to provide improved features, such as faster response times and better accuracy in location determination. While providing substantial improvements over their predecessors, present-day public safety systems still fail to provide an automated “accountability” feature. Accountability refers to the tracking of public safety personnel, such as firefighters and police officers, at the scene of an emergency. The purpose of accountability is to assist on-scene commanders in managing and accounting for their personnel by providing regularly updated locations of these individuals. Since emergency personnel are often moving rapidly, the location data desired for accountability is not necessarily absolute location of personnel, but rather the general area or zone location of such personnel. For example, the on-scene fire commander need not know the step-by-step location of a firefighter, but whether the firefighter is outside the building, on the roof, on the first floor, in the rehabilitation area, and so forth. Hence, accountability provides improved organization for emergency personnel at an emergency scene.
Conventional methods for monitoring accountability are tedious and inaccurate. For example, under one conventional accountability approach, public safety personnel (e.g., firefighters) are issued tags. The tags are typically affixed to pads on each individual's gear or helmet. Upon entering an emergency scene, the tags are collected from each individual within a unit and tracked on a board. If an individual switches locations or gets reassigned to work in another zone of the scene (e.g., with another work group), the reassigned individual's tag is supposed to be moved accordingly on the board. The tag approach requires the individual to radio in his or her location to the commander. In a chaotic emergency environment, however, personnel may switch locations and/or work groups without remembering to report back their change in location. Thus, the tag approach does little to accurately track the location or movement of (i.e., account for) an individual.
For tracking individuals in an ad hoc work area, such as an emergency scene, one current approach employs a computer and a base station transceiver operated by an individual, such as an incident commander, together with portable radios used by the individuals. In this type of tracking system, the work area is divided by the incident commander into multiple zones or sub-areas. Each zone is assigned a channel number. The channels are selected by a rotary channel selector on each portable radio. The individual radio user manually selects the appropriate channel number according to their work group assignment and zone. The base station transceiver receives all the transmitted signals and provides the radio identifications and their channel numbers to the incident commander's computer. An accountability application running on the computer converts the channel numbers to zones and displays the locations of the individuals by radio identification and zone. However, this type of approach is wholly reliant on the individual's reporting of his or her zone location by remembering to change channel number on the radio. In addition, since vision may be impaired during an emergency (e.g., due to smoke) and manipulation of the channel selector may be inhibited (e.g., due to the use of bulky gloves), the individual may inadvertently select the wrong channel/zone, thereby hindering the accountability aspect of the system.
Various location determining technologies, such as the global positioning system and radio frequency triangulation, presently exist to estimate the absolute location of a wireless communication device and, accordingly, the individual presently using the wireless device. While absolute location is desirable in certain emergency situations, such as to locate a wireless device that was used to place an E-911 call, absolute location of emergency personnel at an emergency scene is generally much more information than is necessary to accurately account for the emergency personnel.
Therefore, it would be highly beneficial, particularly (although not solely) in emergency situations, to monitor a zone location of a wireless device in a partitioned geographic area with little or no interaction by the user of the wireless device.